There are a number of medicament delivery devices on the market in which a medicament container is placed, usually in an appropriate container holder designed to accommodate the medicament container.
Many medicament delivery devices are arranged with a number of automatically triggered functions such as penetration, injection, withdrawal, protection of a medicament delivery member after delivery, just to mention a few.
Many of these functions require a number of components, making the device rather complex, as well as require handling aspects that may be difficult for some users, even though the functions as such are automatic. There are also aspects regarding the interaction between different components requiring handling tolerance chains that may be quite complex when a number of components are to interact.
It is thus in many devices a desire to keep the number of components as low as possible in order to reduce the complexity of the functions as well as reducing the tolerance chains. Also in view of handling and administration of medicament the number of components of the device should be kept as low as possible in order to provide a clear and concise operation.
Further, according to the type of drug and the ailment which the medicament is designed to alleviate, every medicament should have a most appropriate injection depth to achieve high efficacy. Therefore, any leakage of medicament before a needle tip arrive the expected injection depth might lose the expected efficacy. Therefore it is desirable that the injection does not start already during penetration, which otherwise often is the case when one spring, acting on a plunger rod, performs both penetration and injection. On the other hand it is often necessary to use two springs when first a penetration is performed followed by an injection.
There is thus room for further improvements in the technical area of medicament delivery devices with a certain amount of automatically performed functions.